docs: def normalize_build_spec(self, build_spec):
          """
          Convert a build spec into a list of Command tuples.
          After running this command, self.build_cmds should hold all
          the commands that should be run on the disk in self.disk_path.
  
          Args:
              build_spec (dict): The buildspec part from the init file
          """
          for cmd in build_spec:
              if not cmd:
                  continue
              cmd_name = cmd.keys()[0]
              cmd_options = cmd.values()[0]
              cmd_handler = self.get_cmd_handler(cmd_name)
              self.build_cmds.append(cmd_handler(cmd_options))